Photographic emulsion containing tricarbocyanines



Oct. 12, 1937. G. s. B'ROKER 2,095,854

PHOTOGRAPHIC EMULSION CONTAINING TRICARBOCYANINES Filed Jan. 1e, 193s m 'l1 78 82 8b 90 94 98 [OZ )3 t i man o Leslzbrodfel;

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Patented Oct. 12, 1937 amasar PHOTOGRAPHE? EMULSION CUNTAINING TRKCARBUCYANINES v Leslie G. S. Brooker, Rochester, N. Y., assignor, by mesne assignments, to Eastman Kodak Company, Jersey ity, N. l., a corporation of New Jersey Application January lr6, 1933, Serial No. 652,029

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flihis invention relates to photographic emule sions, and more particularly -to gelatine-silver `halide emulsions, sensitized to the deep and infrared regions of the spectrum by rcertain tricarbocyanine dyes, which are cy'aninedyes containing a seven-methenyl chain.

Novel trlcarbocyanines which I have found useful are the thiazolinotricarbocyanines, the thiazolotricarbocyanines, the selenotricarbocyanlnes and the 4,4tricarbocyanines. The latter is unique in that it sensitizes emulsions further into the infra-red than any dye heretofore known or suggested. Other tricarbocyanines which i r have found useful for sensitizing photographic emulsions are the thiotricarbocyanines, the benzothiotricarbocyanines and the 2,2tricarbocya nines. l v

It is an object of my invention to providephotographic emulsions and/or elements sensitive to the infra-red region of the spectrum. Other objects will hereinafter appear.

To utilize the sensitizing properties of these dyes one merely incorporates the dye in the photographic emulsion, which it is desired to sensitize such as a gelatino-silver-halide emulsion, or the photographic element coated with the emulsion may be bathed in, or coated with, a solution lof the dye.

The dyes herein referred to are fully disclosed, with appropriate examples of their preparation, in my copending applications Serial Nos. 651,870 and 652,030, led of even date herewith.

The constitution of these dyes is illustrated by the following formulas. For instance the thiazolinotricarbocyanines, which are derived fromthe condensation of two thiazoline nuclei, by the methods disclosed in my above applications, have the following formula- /S S\ n c \\c=oH-cH=cH-cH=GHoH=oH-c/ im Hl CH2 \N /N 45 fr l v R \X.

where R=alkyl, such as methyl, ethyl, etc. and X==acidic'radical,such as halide, etc.

'I he thiamlotricarbocyanines have the general or groups such as hydrogen, methyl, phenyl, etc. p

60 and R and X have the significance given above.

` glutaconic (Cl. S35-'1) The selenotricarbocyanines have the general formulawhere R. and X have the signicance given above. The lepidine nucleus ymay or may not be sub'- stituted, as for instance by such groups as methyl or ethoxy.

The following examples, taken from my aboveA referred to copending applications, serve to illustrate the preparation of the tricarbocyanine' dyes employed in my invention. These examples are not intended to limit my invention.

` EXAMPLE 1 2,2#Diethylselenotricarbocyanine bromide 2 parts (2 mols) of l-methylbenzoselenazole are heated for a day with 2 parts (2'mols) of 'ethylVp-toluenesulfonate at 100. The product is dissolved in 12 parts of absolute ethyl alcohol, the .solution chilled in ice-water, 1.4 parts of aldehyde -dianili'de hydrochloride added followed by 0.85 parts (2 mols) ofpiperidine. The dye is rapidly formed and the whole is allowed to stand for several hours at room tem-v.

perature or somewhat lower. 'I'he dye is then precipitated with aqueous potassium bromide, collected, washed clean with water followed by acetone, and purified by recrystallization frommethyl alcohol.

It separates in beautiful green needles and gives a deep greenish blue solution.

' EXAMPLE 2 1,1 Diethyl4,4'-tricarbocyanine iodide 12 parts `(2 mols) of lepidine ethiodidewere dissolved in 25 -parts of absolute ethyl alcohol and the solution chilled in a freeiting mixture with stirring, so as to obtain very smallfcrystals l of the Quaternary salt. 5.6 parts (1 mol.) of glutaconic aldehyde dianilide hydrochloride were then added, with cooling and shaking. A dark coloration rapidly developed and the whole was stood aside in the ice box overnight. Next morning the muddy liquors were filtered off, the residue washed with acetone until most of the tarry impurities had disappeared, followed by water and then more acetone. The residue was next boiled f with a small quantity of methyl alcohol, cooled and iiltered, and this treatment repeated onceor twice until the filtrate was clear green color and the dye on the lter looked clean. It then consisted of coppery crystals and gave a somewhat dullgreen solution. The ,dye could be successfully recrystallized from methyl alcohol, especially if the hot liquors were chilled so as toexpose the dye to the action of the hot alcohol for Emmi: 3

2,2'-Diethylthiazolinodricarbocyanine iodide 5.1 parts (2 mols) of 2-methy1thiazoline were heated for 4 hours at 100 with 10 parts (2 mols) of ethyl-p-toluenesulfonate. The yellowish viscous product was used without further purifi-vv cation, being dissolved in 25 parts of ethyl alcohol, the solution well chilled in a freezing mixture, 7 parts (1 mol.) of glutaconic aldehyde dianilide hydrochloride added to the solution followed by 4.3 parts (2 mols) of piperidine. There was an instant' very dark coloration and the whole was stood aside in the ice box overnight. Crystals of the p-toluenesulfonate of the dye separated on stirring in 'l0 parts of cold ether. 'I'he ethereal layer was poured oi and the residue stirred with 40 parts of acetone and filtered. 'I'he yield of air-dried dye is around 80%. The

dye is then dissolved in hot methyl alcohol (25 parts) and precipitated by adding a solution of excessofpotassium iodide (10 parts) in hot water (25 parts).

dissolved with a deep blue color.

, Exnn u14 3,3'Diethylthazolotriearbocyanine iodide 2-methylthiazole etho-p-toluenesulfonate is prepared by heating 4 parts (2 mols) of 2- methylthiazole with S-parts (2 mols) of ethyl ptoluenesulfonate for 30 hours at 100. The product is dissolved in 20 parts of absolute ethyl alcohol, the solution chilled in ice water, 516 parts (1 mol.) of glutaconic aldehyde dianilide hydrochlorideadded .and then 3.4 parts (2 mols) of piperidine. The whole is well shaken and stood in the ice box for about' 120 hours. 'I'he deep blue liquid is then mixed with an excess oi.' cold .f

aqueous potassium iodide and the die is precipitated, removed by filtration and washed with water. It is then treated with acetone, in which it dissolves readily, and on standingor on rubbing with a .glass rod the dye separates out in The steely crystals could be crystallized from methyl alcohol in which they beautiful greenish bronze crystals relatively insoluble in the solvent. 'I'hese crystals are removed and may be recrystallized from methyl alcohol, the color of the solution being deep blue. 'I'he dye is then obtained in green needles, some facets of which reect blue light and others brassy-green light.

EXMPLE 5 3,4,3,4-Tetramethylthiazolotricarbocyanine bromide 12' parts (2 mols) of 2,4-dimethylthiazole metho-p-toluenesulfonate (made by condensing together equimolecular proportions of 2,4-dimethylthiazole and methyl p-toluenesulfonate) are dissolved in 24 parts of hot absolute ethyl alcohol, the solution rapidly chilled in a freezing mixture, 5.6 parts (l mol.) of glutaconic aldehyde dianilide hydrochloride added, 3.4 parts (2 mols) of piperidine, the whole well shaken, and stood aside for 6 days at 0-10 C. with occasional shaking. The dye separates out and is removed by filtration at the end of the period, impurities being removed by washing with acetone followed by water. The dye (probably the p-toluenesulfonate) forms a dull green'powder which may be recrystallized from methyl alcohol, or, the methyl alcoholic solution may be treated with excess of aqueous potassium bromide, when the bromide of the dye separates out. This may be removed and recrystallized from methyl alcohol and it separates in green lustrous crystals which give a deep blue solution.

EXAMPnE 6 3,3-Dimethylthiazolinotricarbocyanine iodide 2 parts of. 2-methylthiazoline are heated at C. for 20 minutes with 3.7 parts of'methyl p-toluenesulfonate to produce 2-methylthiazoline vmetho-p-toluenesulfonate (2 mols). This salt is dissolved in 25 parts of pyridine, the solution cooled and 3.6 parts (1 mol.) of 2-iodopyridine ethiodide added and the mixture kept at room temperature for 5 days with occasional shaking. The dye is then thrown out of solution by adding much ice water and is removed by ltration. It

may be recrystallized from methyl alcohol in which it gives an intense blue solution and is obtained in blue grey crystals.

EXAMPLE 7 2,2' Diethyzthiotricarbocyanme iodide Other bases such as n-butylamine, pperidine,

mols) is used in place of the Quaternary salt usedv above, the dye obtained is 2,2-diethyl 5,6,5',6'-dlbenzthiotricarbocyanine iodide which crystallizes in coppery crystals which-give a green solution in alcohol.

, ExAimrmS vanwaar-Mmmm@ iodide.

6.9 parts (2 mols) of quinaldine etho`p-tol uenesulfonate, 2.8 parts (1 mol.) of glutaconic,

aldehyde dlanilidehydrochloride and 22 parts of absolute ethyl alcohol are mixed up together and the suspension chilled in a mixture of ice-aud concentrated hydrochloric acid. 1.7 parts (2 mols) of piperidine are then added. with shaking and the whole kept at about 0- C. for a day.

. The diagrammatic spectrograms constituting.

the accompanying drawing illustrate the regions of the spectrum'towhich the various types of dyes herein disclosed will sensitize a gelatinol silver-halide emulsion and the extent of the senthis drawing and the dyes, the sensitizing properties of which they illustrate, are as follows- Fig. 1. 3,3diethyl-thiazolinotricarbocyanine iodide. l

Fig. 3. 2,2'diethy1selenotricarbocyanine bromide. Y

The sensitization'resulting from the various other dyes herein referred to and belonging to the respective classes o1' dyes above illustrated are all comparable to the sensitizationillustrated as resulting from the speciilc dyes named in connection with these gures.

The preparation of gelatino-silver-halide emulsions are well known to those skilled in the art. To sensitize such emulsionsI prepare a stock solutionof the dye -by dissolving the dye in alcohol. 'Ihen in one liter of the emulsion I'thoroughly incorporate, normally, a volume of the stock solution which contains from approximately 3/5 to one mg. of the dye and spread the emulsion upon -a suitable support, such as glass 'or cellulose derivative sheeting, to a suitable above indicated.

thickness and allow it to dry. Photographic elements so prepared are best stored in the c o1d` inherent instability-of these dyesl at elevated temperatures.

The amount of dye which is actually' incorporated in a given quantity of emulsion will, of course, vary from dye to dye and emulsion to emulsion, as is known to those skilled in the art. The above figures are, therefore, to be regarded only as illustrative as it may be necessary in some cases to use more or less ofthe dye, than I have Under the class of gelatino-silver-halide emulsions I, of course, include all of the silver halides .customarily employed in the art but more ,par-

. nines, and' selenotricarbocyanines. sitization at various wave lengths. The figures of 2. A gelatino-silver-halide emulsion sensitized with a thiazolinotricarbocyanine dye.

3. A gelatino-silver-halide emulsion sensitized with a selenotricarbocyanine'dye.

4. A gelatino-silver-halide emulsion sensitized withl a 3,3dialkylthiazolinotricarbocyanine salt.-

5. A gelatino-silver-halide emulsion sensitized with a 1,1'dialky1selenotricarbocyanine salt.

6. A gelatino-silver-halide emulsion sensitized 'with a 3,3'-diallylthiazolinotrlcarbocyanine iocyanines, thiazolinotricarbocyanines, and selenotricarbocyanines.

9. A gelatina-silver-halide emulsion sensitized with 2,2'dietlrvlselenotrlearbocyanine bromide. 10. A gelatine-silver-halide emulsion sensitized with 3,3'diethylthiazolinotricarbocyanlne iodide.

Lnslmasnnoom. 

